In general, a “reply to all button” is provided in addition to a “reply button” on a mail data display screen that displays mail data received. When the user selects the “reply to all button,” the mail data display screen is shifted to a reply mail data generation screen in which a TO destination included in the mail data received is inputted in advance in a TO destination input field and a CC destination is inputted in advance in a CC destination input field. Since the TO destination and the CC destination are inputted in advance on the reply mail data generation screen, the labor hours required by the user to input mail addresses can be reduced.